*{
  margin: 0;
  padding: 0;
}
body{
  background: url('../img/suihua.jpg');
}
/* 隐藏 */
.hidden_box{
  display: none;
}
/* 显示 */
.show_box{
  display: block;
}
/* 父盒子 */
.big_vessel{
  position: absolute;
  left: 50%;
  top: 50%;
  margin-left: -400px;
  margin-top: -400px;
  width: 800px;
  height: 800px;
}
/* 信封 */
.envelope_box{
  position: absolute;
  top: 50%;
  right: 50%;
  margin-top: -175px;
  margin-right: -250px;
  width: 500px;
  height: 350px;
  background-color: rgb(255,255,255);
  border-radius: 20px;
  box-shadow: 8px 8px 8px #666;
}
/*阴影三角*/
.shadow_box{
  width: 100px;
  height: 0;
  border-width: 200px;
  border-style: solid;
  border-color: rgb(0, 0, 0,0.1) transparent transparent transparent;
  border-radius: 20px;
}
/*覆盖三角*/
.lid_box{
  position: absolute;
  top: 0;
  left: 3px;
  width: 100px;
  height: 0;
  border-width: 197px;
  border-style: solid;
  border-color: rgb(255,255,255) transparent transparent transparent;
  border-radius: 16px;
}
/* 印泥 */
.ink_pad_box{
  position: absolute;
  top: 50%;
  left: 50%;
  margin-top: -20px;
  margin-left: -50px;
  width: 100px;
  height: 94px;
  line-height: 94px;
  text-align: center;
  background: url(../img/印泥2.png);
}
/* 文字 */
.ink_pad_box span{
  cursor: pointer;
  color: rgb(255, 255, 255);
  user-select: none;
}
.ink_pad_box span:hover{
  color: transparent;
}
/* 信纸 */
.paper_box{
  position: absolute;
  top: 50%;
  right: 50%;
  margin-top: -350px;
  margin-right: -275px;
  width: 550px;
  height: 700px;
  line-height: 2em;
  text-align: center;
  border-radius: 20px;
  background-color: rgb(255, 255, 255,0.7);
  box-shadow: 8px 8px 8px #666;
}
.content_box{
  position: absolute;
  top: 102px;
  left: 0;
  padding: 40px;
  user-select: none;
  /* 文字渐变色(利用背景渐变,裁剪文字以外的地方,设置文字透明即可) */
  background-image: -webkit-linear-gradient(#02d9d2, #ff459a);
  -webkit-background-clip: text;
  color: transparent;
}
.return_button{
  position: absolute;
  bottom: 0;
  right: 40px;
  width: 100px;
  height: 30px;
  color: #ff459a;
  text-align: right;
  cursor: pointer;
}
.return_button:hover{
  color: transparent;
}